Northern Ireland's largest
food-processing company, Moy Park Ltd., pledged Thursday to discover how
a potentially cancer-causing drug ended up in up to 23 tonnes of its free-range
chickens.

The United Kingdom's Food Standards Agency warned
consumers in Britain and Ireland to discard frozen Moy Park-produced chickens
or chicken parts after tests at the firm's largest plant in Dungannon found
traces of the anti-bacterial drug nitrofuran in one batch. Moy Park said
it didn't know how the drug got into the food chain.

"Organic birds are reared outdoors. It could
be some incursion from outdoors," said Moy Park spokesman Gareth Jones.
"So we are looking at the soil, the grass, chemicals used to clean
the houses - whatever. Everything needs to be looked at and no blade of
grass, no stone needs to be left unturned."

The suspect poultry had use-by dates from Oct. 8 to
Oct. 12, so has already largely been consumed unless stored in freezers.
It was sold at several British and Irish supermarket chains, including market-leader
Tesco.

The European Union banned the drug - which is added
to animal feeds or applied topically to wounds - from use in food-producing
animals in 1995 after research found it could cause cancer in humans, but
only if consumed over a prolonged period. The U.S. Food and Drug Administration
imposed its own ban in 2002.

The drug continues to be used in other parts of the
world, particularly in Asia, to prevent bacterial infections in cattle,
fish, swine and poultry.

Moy Park is one of Europe's leading poultry companies,
employing more than 3,800 people in six factories in Northern Ireland and
France. The Dungannon plant 65 kilometres west of Belfast processes 1.1
million birds a week.

The company has been exporting chicken products since
1963 to Britain and in the 1990s acquired two plants in France, one of which
produces sandwich meats.